Does Femoral Nerve Catheter Placement with Stimulating Catheters Improve Effective Placement? A Randomized, Controlled, and Observer-Blinded Trial

Abstract

Continuous peripheral nerve blocks offer the benefit of extended postoperative analgesia and accelerated functional recovery after major knee surgery. Conventional nerve localization is performed over a stimulating needle followed by blind insertion of the peripheral catheter. Correct catheter placement is confirmed by testing for satisfactory analgesia. Stimulating catheters offer the advantage of verifying correct placement close to the nerve during catheter placement. The aim of this randomized trial was to determine whether accurate catheter positioning under continuous stimulation accelerates the onset of sensory and motor block, improves the quality of postoperative analgesia, and enhances functional recovery. We compared femoral nerve catheters inserted under continuous stimulation with catheters that were placed using the conventional technique of blind advancement in 81 patients undergoing major knee surgery. Time of catheter placement was similar in both groups with 4 min (3/7.3; median, 25th/75th percentile) in the conventional group and 5 min (4/8.8) in the stimulating catheter group. In both groups, 42% of the catheters could be correctly placed (motor response of the patella with a current < or =0.5 mA) at first attempt. In 22 patients (58%) of the stimulating catheter group, the catheter had to be redirected 1-20 times, including 2 that could not be correctly placed within 20 min. The onset time of sensory and motor block was almost similar in both groups. There were no differences in the postoperative IV opioid consumption, and visual analog scale pain scores at rest and movement, or maximal bending and stretching of the knee joint during the 5 days after surgery. We conclude that with continuous femoral nerve blocks, blind catheter advancement is as effective as the stimulating catheter technique with respect to onset time of sensory and motor block as well as for postoperative pain reduction and functional outcome.

Efficacy of Continuous Femoral Nerve Block with Stimulating Catheters Versus Nonstimulating Catheters - A Systematic-Narrative Review

“…Morin et Al. (Morin et al, 2005) in the following year published the results from the comparison between femoral nerve catheters inserted under continuous stimulation and catheters that were placed using the conventional technique of blind advancement in 81 patients undergoing major knee surgery. The aim of his randomized double blind trial was to determine whether accurate catheter positioning under continuous stimulation accelerates the onset of sensory and motor block, improves the quality of postoperative analgesia, and enhances functional recovery.…”

“…However, they were surprised to find that the amperage required to elicit motor responses is higher with the stimulating catheter than with the introducer needle. In a study performed by Morin et al (Morin et al, 2005), the authors did not find a relationship between the current that had to be applied via the stimulating catheter to evoke a motor response and any of the variables determined to judge the success of the catheter positioning. Viewing this works, doubts may arise regarding the reliability of stimulating catheter to elucidate motor contruction and to determine correct catheter positioning.…”

Ultrasonography and stimulating perineural catheters for nerve blocks: a review of the evidence

“…Moreover, no study has formally compared the equipment available for stimulating catheter insertion. RCTs have used alternately different kits: the Arrow StimuCath Continuous Nerve Block Set (Arrow international, Reading, PA, USA); [23][24][25]27 an 18G, 85-mm long needle, oversheathed with a plastic introducer set (Multiplex, Vygon, France); 28,29 a 50-mm, 18G needle with a stimulating catheter (Polymedic C-50 K +); 26 or a 22G, stimulating catheter with a 19.5G, 100-mm needle set (Stimulong Plus, Pajunk, Geisingen, Germany). 30 Further studies are required to compare the electrical properties of these kits.…”

“…in 81 patients undergoing TKR (n = 60) or ACL repair (n = 21), Morin et al 27 compared blind and stimulating femoral catheters (median stimulation threshold of the catheter = 0.2 mA; pulse width = 0.3 msec). Both catheters received a bolus of 20 mL of prilocaine 2% and an infusion of ropivacaine 0.2% (6 mL·hr -1 for 48 hr).…”

“…The authors did not perform a single shot SB. Morin et al 27 found no technical differences pertaining to catheter placement (procedural time, patient satisfaction, and anesthesiologist's evaluation of the difficulty encountered). After the bolus, no differences were noted in the onset of sensory and motor blockade.…”